A court which has issued a permanent injunction may, under certain conditions, open and modify or dissolve the injunction even though the decree in the original action has become final. This power is said to be justified by the continuing operation of the injunction, which regulates future conduct as well as determining the rights of the parties as of the date of rendition of the decree. The same proposition can be restated by saying that injunctions are issued to protect existing rights, but provide no immunity against modification of those rights because of later changes in the applicable law or the essential facts.
Charles B. Blackmar S.Ed.,
INJUNCTIONS-POWER OF A COURT TO MODIFY A FINAL PERMANENT, INJUNCTION,
Mich. L. Rev.
Available at: https://repository.law.umich.edu/mlr/vol46/iss2/7